This invention relates to apparatus for applying decorative rings, concentrically arranged inscriptions, labels, ornamental designs and the like, to rotationally symmetrical rubber articles, especially to the visible surface disposed inboard of the treads of pneumatic tires. Vehicular tires provided with such decorative rings are known generally as "whitewalls". But with the present apparatus, rings of one or more colors of variable widths may be readily applied to the tires, also letters, symbols or other decorations, may be arranged in one or more concentric rings.
Methods and apparatus for applying similar decorative rings and the like, according to the present state of art, are generally applied to the tires after removing them from the rims of their supporting wheels. Such processes are therefore complicated and somewhat time-consuming. There is a known method in which the tire remains on the wheel's rim as well as on the vehicle (see British Pat. No. 1,592,003), but according to this method, the entire vehicle is placed on an elevating platform, and preliminary preparation techniques include cutting an annular groove in the side walls of the tire by means of a manually operated grinding wheel, whereby considerable expertise is required to produce the precise rounded groove of uniform width necessary for the success of the operation.
U.S. Pat. No. 3,218,208 of Molen discloses a device in which the groove required for embedding a decorative strip on a vehicle tire may be formed mechanically independently of an operator, with the tire remaining on the wheel's rim. To accomplish this, the apparatus comprises a vertically arranged rotatable shaft, on the end of which the wheel may be secured by means of a centering cone. A milling cutter, driven by a rotatable shaft fastened to an adjustable arm, cuts a groove into the side surface of the pneumatic tire mounted on the wheel's rim. But, the process of embedding a color strip into a vehicular tire, together with the necessary vulcanization process, cannot be performed by this device.
French Patent 2,386,413 for repairing tire treads or shoulders, discloses a device by which rubber strips may be applied on a vehicle tire when removed from the wheel's rim. To accomplish this, the tire is vertically disposed on a support surface and rolled, engaged on both sides with rotating driving disks, which simultaneously position the tire whereupon, on each of both sides, a rubber strip is pressed simultaneously against the tire by a rubber roller or brush. This device, however, is not intended for the application of decorative rings. With a vertically disposed tire, monitoring the precise placement of decorative rings is also difficult without removing the tire from the device; also, with this device, strips which have been pressed on must then be vulcanized together with the tire by a special vulcanizing apparatus.
Cutting an annular groove in the side surface of a modern tire, into which groove a prefabricated decorative ring may be embedded after napping (roughening) and coating with a vulcanizing solution, is disadvantageous to the stability and strength of the tire. Pressure and heat are required to vulcanize the tire surface in a mold and the complicated process which is involved is aggravated by the fact that modern tires have very thin rubber sides.